The present invention is concerned with a sustained release pharmaceutical composition, and in particular is concerned with a sustained release pharmaceutical composition which contains a pharmacological material; a binding agent for the pharmacological material; and a matrix of a water-insoluble but water-swellable hydrophilic polymer. The present invention is also concerned with methods for preparing the pharmaceutical compositions.
It has previously been suggested to incorporate drugs into hydrophilic polymers to provide sustained release of the drug. However, the particular drugs which have to date been satisfactorily employed in such a sustained release mechanism are very limited since not every combination of a drug and any type of hydrophilic polymer provides a suitable slow release mechanism. Furthermore, such systems are not very susceptible to tailoring the release for a particular application. That is, the slowing down or speeding up of a release system is not readily accomplished. In addition, many prior suggested sustained release pharmaceutical compositions require relatively large quantities of synthetic materials.
Accordingly, it is an object of the present invention to make it possible to provide sustained release pharmaceutical compositions which are applicable for a large variety of pharmacological agents. Another object of the present invention is to provide a means by which it is possible to selectively alter the release characteristics for a particular application. A further object of the present invention is a reduction in the quantity of synthetic materials without a concomitant reduction in the release characteristics of the pharmacological compositions.